In the field of mining, excavating and earth working machinery, holders are fixed to the machinery for presenting bits or teeth in proper working positions so they may be driven against the face of the material to be mined, excavated or worked. One type of bit member utilized for mining purposes is in the form of a pick-like bit member, the body of which is symmetrical about a longitudinal axis and has a shank at one end for support of the body, and is tapered inwardly at the other end where there is provided a hard region or a hard insert, such as a cemented tungsten carbide insert. In the use of the pick-up bit member, it has been found that the bit members or the inserts wear rapidly and must frequently be removed and reconditioned or replaced. This involves expensive down time of the machine using the bit member and greatly interferes with maintaining the proper rate of production.
To facilitate the replacement of bit members it has been known to form the shank of the elongated bit member with an annular groove in which is mounted a split-type keeper ring that is held captive on the shank. The keeper ring is usually formed with projections which aare received in recesses in the body which opens into the bore to hold the bit member in the supporting body. Examples of prior art resilient keeper rings are disclosed in U.S. Pat. Nos. 3,519,309; 3,752,515; and 3,767,266.
Heretofore, prior art keeper rings have been provided with radially spaced, circumferentially located projections in the form of dimples or the like, and such projections engage recesses in the bore of the support block merely due to resiliency of the ring wall. Accordingly, it would be of significant advantage to provide a keeper spring having increased or redundant spring resiliency for maintaining the bit member within the supporting holder, and such an advantage is an object of the present invention.